Honing tool



July 13, 1948. c. E. BECK 2,445,015

uonme moon Filed March 25, 1946 III'IIIIH'III I'III'IIIII" IlIlIlIIlIlll/IlllllfillllIllm INVENTOR. CARL 5.. BECK ATTORNEY BY s Q h Patented July 13, 1948 UNITED STATES PATENT OFFICE a 2,445,015 a a a Home TOOL I I 7 Carl E. Beck, San Francisco, Calif.

Application March 25,1946, Serial No. 656,8

6 Claims.

This invention relates to honing tools and more particularly to means for abrasive finishing small holes. I

Among the objects of the invention is the provision of means for finishing holes to fine tolerances.

Another object is the provision. of means for accurately and positively advancing the abrasive element with micrometric precision, I

Another object is to adapt a single tool to various sizes of relatively small. holes.

A further object is to protect the mandrel from abrasive wear. r

After heat treating a piece of steel having holes therein, the holes are shrunken to asmaller size and often distorted out of round. The metal is thentoo hard to drill or ream accurately,- but can,

be abraded or honed to precision by the present invention. V I a Other objects and advantages will appear as the description progresses. and the accompanying drawings the invention is disclosed in its present preferred form. But it is to be understood that it is not limited to this form, because it may be embodied in modifications within the spirit of the invention as defined in the claims following the description.

In the one sheet of drawings:

Fig. 1 isalongitudinal vertical section of a honing tool constructed in accordance with this invention, on the line II Fig. 2. 1

Fig, 2 is a plan view from above of the same,

partially broken away to disclose the underlying bar retracting spring.

Fig. 3 is an end view of the same.

In detail the structure shown in Fig. 1 comprises th cylindrical mandrel I, of the desired diameter and heat treated and ground to the desired size, up to the shoulder at 2, of the head 3. The head has the external threaded portion, upon which Vernier sleeve 4 isthreaded and has the graduated scale 5 reading with the index :6 on the head. This sleeve, has the knurled-portion 1.

The exterior of the head 3 may be parallel as shown for chucking in a lathe, or it may be tapered for use-in a drill press or other reciprocating drive. The head is center bored at 8 up to the shoulder 2, andis closed at the end by the plug 9 threaded therein- The mandrel I- has the longitudinal slot I! I milled therein from the outer end into the head 3, to meet the center bore 8. The plunger [2 has the stem I3, telescoping into the expansive spring l4, interposed between the plunger and the plug 3.

2 I sleeve 5. The forward end of the. plunger l'2 is transversely reduced and has the upstanding pin l9. 7 I

Referring to Fig. 2, the bottom of the slot II has the interspaced cams 20, 2|, fixed therein by studs passing through the body of the mandrel l and riveted in countersunk holes therein. The spring ,detent 22 is also fixed to the bottom of this slot and held by the rivet 23, similarly riveted to the body of themandrel. This detent consists of a piece of hard wire bent back uponitseli to form a loop held by the rivet 23, with its pro- In the specification jecting extensions adjacent the sides of, the slot II. The endsof these extensions are bent upward at 25 and directed toward the open end of theslotll. f i H The hone holder, Fig. 1, consists of the bar 26 transversely milled away to form theoverhanging end 21 with a hole therethrough engaging the pin IQ of the plunger l2. The inclinedcam faces at 28, 29, ride on the cams 20,, 2|, to extend and retract the bar 26 relative to the diameter of the mandrel l. The longitudinal rib 30, hasthelat eral lugs at 3i on its opposite sides, which engage beneath the extensions of the wire detent22 to normally retract the bar 26 into the slot ll; The hone 32 is shaped to removablyfit into a longitudinal groove in theouter face of the bar 26, flush with the periphery of the mandrel I, see Fig. 3. This hone is formed of a suitablybound grit of the desired grade adapted to the type of metal to be abraded. I f v The bar 26 is assembled into the slot H by dropping it into the slot with the lugs, at3l ahead of-the upturned ends 25 of the wire detent 22. Then the bar is forced backwardly. As the bar is moved rearwardly, the upturned ends 25 of the detent ride upwardly over the lugs and urge the bar outwardly on to the inclined cams at 20.. Thev segmental sleeve 33 telescopes' over the length of the mandrel I,, up to the shoulder 2 This sleeve is made of a hardheat treated alloy and. ground to the diameter desired. Its function is to enable the adjustment of the mechanism to a range of sizes by substituting sleeves such'as 33. In the larger sizes a thicker hone 32 can be substituted to match the diameter of the sleeve 33. This sleeve has the further advantage that it takes the lapping wear incidental to waste grit that may accumulate between it and the inner diameter of the hole being lapped, thus saving the The plunger retractor I 5 is slidable on the head 3, and hasthe annular internal groove l6, en gaging the stud l1 threaded into the plunger l2 through the hole l8 in the, retractor. Acting through this'stud, the spring l3 maintains the retractor under spring tension against the Vernier the tension of the spring M, the tension of which may b regulated by the screw plug 9.

The end of the mandrel is then inserted in the hole to be honed and the retractor I is released until it abuts the 'v'ernier sleeve 4 that has been adjusted to hone the hole to the calibrated sizev While the mandrel and hone 32 are being rotated, the drill press head is reciprocated up and down to cause a lapping action of the hone against the wall of the hole being honed. This prevents concentric scoring of this wall and insures a uniform texture of the wall. Occasionally the swivel retractor I5 is lifted to slightly release the hone from the Wall of the hole to clear accumulated waste grit and abraded metal, which collects in thespace between the edges of the segmental sleeve. 33 and the slot l l'.

When the swivel retractor i5 is released the spring I l pushes the bar 26 up the inclinedcams 20, 21 iandlforces the hone gently against the wall of the hole, permitting it to perform its abrasive function.

Average mechanical ability is all that is required to operate this invention, after the Vernier adjustment at 5 is set tovthedesired calibration, preventing anoversize honing of the hole.

V-Inthis -art threeeighths of an inch is considered a smallholebutby appropriate precision in constructingithis invention smaller-sizes can be so' honechbecause of'the simplicity andrdirect action of the structure of the invention. Itis equally adaptable to the honing of such. holes -or cylinder bores. in thelarger sizes,

nI-Iaving fully described this invention. and-its mode otoperation, what I claim and desireto secureiby Letters Patent is:

:1. --A honing tool comprising a mandrel having a iheadwith a center bore therein, and a longitudinal slot insaid mandrel open to said centerbore and having aniinclined bottom portion; a bar-slidable: inasaid slot and having inclined portions slidable on said bottom; a hone supported :on'said bar, a 'vernier stop "threaded on said head; a plunger. slidable in-saidhead and engaging-said bar and -havingsa stud extendin through said slot; a plungerrretractor slidable on said head and engaging said stud; and aspringin said center bore .and. bearingagainst said -plunger,,.said vernierstop acting to limit the-forward movement of said plunger 'retractor and cooperatin therewith to regulate th'eextent ofoutward movement of thesaid bariand hone.

2. a A honing tool comprising mandrel having a head with a center bore therein, andva longitudinal slot in said mandrel and extending into said centerbore; a pair of cams in the bottom of saidslot; a bar slidable in said slot and, having cam portions engaging said camspawhone supported on said bar,- resilient means normally extendingsaid bar into said slot; a -vernier stop threaded on saidhead; a plunger slidablein said head and engagingsaid bar and having avstud extending through said slotya plunger retractor slidable on said head i and engaging said stud; and a springin said vcenterboreand bearing against said plunger, said Vernier stop acting-to limit the forwardmovement of said plunger retractor and cooperating therewith to regulate the extent of outward :movement of the said bar and hone.

BPAhQning tool comprisinga mandrel having ahead with acenterboretherein, and a longitudinal slot in said mandrel open to said centerbore; interspaced inclined portions on the bottom of said slot; a-barIs'lidable in said slot and having cams engaging said inclined portions; a hone supported on said bar, lugs on said bar intermediate said cams; a resilient means fixed to said bottom and engaging said lugs; a Vernier stop threaded onsaid head a plunger slidable in said oenterbore and engaging said bar and having a stud extending through said slot; a plunger re- :trlactor slidable on said head and engaging said stud; and a spring in said centerbore and bearing *against said plunger, said Vernier stop acting to .l-imitthaforward movement of said plunger retractor and cooperating therewith to regulate the ext'ent of :outward'movement of the said bar and hone.

4. A honing tool comprising a mandrel having a head with a centerbore therein, and a longitudinal slot in said mandrel open to said centerbore and having an inclined-bottomportion;abar slidable in said slot and having inclined portions slidable on said bottom portion; a "hone supported on said bar, a Vernier stop threaded on said head; a plunger slidable in said head and engaging said bar and having a stud extending through-said slot; a plunger retra'ctor slidable on said head and engaging said stud;- aspring in saidcenterbore and bearing-against said plunger; said vernier stop acting'to' limit the forward movement of said plunger retractor and cooperating therewith to'regulate the extent of outward movement of the said bar and hone, and a' segmental sleeve removably surrounding said mandrel;

5.-A honing tool comprising a mandrel having a head with a centerbore therein and alongitudinal' slot in said mandrel open to said centerbore and having an inclined bottom portion; a bar slidable in said slot and having inclined portions slidable onsaid bottom portion; a hone supported on said bar,-a Vernier stop threaded on said head; a plunger slidable in said'head and engaging said bar and having a stud extending through said slot; an -annular plungerretractor having an internal groove engaging said stud; a spring in said centerboreand bearing against said plunger, said Vernier stop actingto limit the forward movement of said plunger retractor andcooperating therewith to regulate the extent of outward movement of the said bar and hone.

"(i-A honing tool comprising a mandrel having a head with a centerbore therein and a longi tudinal slot in said mandrel open to said centerbore and having an inclined bottom portion; a honing barslidable in said slot and having inclined portions slidable on said bottom portions; a hone supported on said bar, a Vernier stop threaded on said head; a plunger slidable in said head and engaging said bar and having a stud extending through said slot; a plunger retractor slidable on said head and having an internal groove engaging said stud; a spring in saidcen terbore and bearing against said plunger; said Vernier stop acting to limit the forward movement of said plunger retractor and cooperating therewith to regulate theextent of outward movement of the said bar and hone, and a segmental sleeve removably surrounding said mandrel on the opposite sides of said slot. 1.

CARL E. BECK. 5 REFERENCES CITED The following, referencesiare of record in the file of thispatent: 7

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